Vascular Medical Device, System And Method

ABSTRACT

The present application discloses a covered stent and a method for navigating the covered stent to a branch vessel, the covered stent including a main body and at least one lateral side branch connected to the main body. A system of covered stents and a method for implanting, including interconnecting the covered stents is also disclosed.

RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. Pat.Application Serial No. 16/888,460 filed May 29, 2020 entitled VascularMedical Device, System And Method, which is a divisional of and claimspriority to U.S. Pat. Application Serial No. 16/304,270, filed Nov. 23,2018, entitled A Vascular Medical Device, System And Method (now U.S.Pat. 11,045,302 issued Jun. 29, 2021), which is a U.S. National Phase ofand claims priority to International Patent Application No.PCT/EP2017/062809, International Filing Date May 26, 2017, entitled AVascular Medical Device, System And Method; which is acontinuation-in-part of and claims benefit of U.S. Pat. ApplicationSerial No. 15/166,141 filed May 26, 2016 entitled A Vascular MedicalDevice, System And Method (now U.S. Pat. 10,821,009 issued Nov. 3,2020); and which claims priority to European Application No.EP16171467.0 filed May 26, 2016 entitled A Vascular Medical Device,System And Method; all of which are incorporated herein by reference intheir entireties.

FIELD OF THE INVENTION

This disclosure pertains in general to the field of medical devices.More particularly the disclosure relates to a vascular medical devicebeing a covered stent, stent graft or endoprosthesis for liquidcommunication with one or more side branch vessel(s), and a system ofsuch devices, as e.g. multiple covered stents for assembly with eachother, and for deployment at a target site in a patient. Also, medicalprocedures for deploying such devices and systems are disclosed. Thetarget site in a patient includes for instance at least a portion of anaorta of a patient. More particularly, treatment of at least a portionof an aorta of a patient by implantation of such a device or system in amedical procedure is disclosed. The medical procedure is preferablyminimally invasive vascular repair.

DESCRIPTION OF THE PRIOR ART

It is known to use modular covered stents or stent grafts for treatmentor repair of vascular disease, such as e.g. an aneurysm. WO 2005/027784discloses a system of modular covered stents for implantation in adiseased vessel, where the covered stents have apertures along themidsection of the covered stent. The apertures are used for aligningwith branch vessels of a main vessel so that further stents can beconnected at an aperture from a main vessel stent. The apertures need tobe precisely aligned with the ostia of the side vessels. From the mainvessel stent, a further stent graft protrudes then from each apertureinto the branch vessel.

An undesired issue with such known devices is that it is difficult forthe operator to correctly implant a covered stent in a main vesselaligned with branch vessels. Apertures or branches from the main vesselcovered stent have to be correctly positioned in the main vessel inrelation to the position of the branch vessels. The branch vessel is tobe in liquid communication with the main vessel, i.e. through branchvessel covered stents or portion of a larger stent graft unit with armsto the branch vessels.

The main vessel covered stent is expanded and thus implanted in the mainvessel. Once expanded and deployed, the main vessel covered stent cannotbe repositioned. Misaligned apertures or branch covered stentsmisaligned with branch vessels may for instance cause kinking of thebranch vessel covered stent. This kinking may cause undesired reducedblood flow to the branch vessel. It may also deteriorate durability andlength of life of the covered stent when implanted, caused by pulsatileflow. It may also lead to leakage, or loosening of a side branch coveredstent unit from a main vessel modular covered stent.

Moreover, there is a certain risk of damaging the vessel when theoperator is trying to find branch vessels using modular covered stentsand in particular in case there is a certain misalignment. Prior artmodular covered stents with apertures pose a further risk of damagingthe vessel walls during operation since they are more or less opencircular apertures facing sideways out of the modular stent. When theoperator then tries to navigate such a side branch vessel into place, asdescribed above, the open apertures may tear or otherwise damage thedelicate vessel wall when being moved around inside the vessel such thatthe vessel wall could rupture leading to internal bleeding. This shouldbe avoided and improved covered stents, or (modular) covered stentsystems, or implantation procedures for the two latter, would beadvantageous.

The aforementioned alignment challenge makes that the operation timewith hitherto known devices and medical procedures becomes often verylong. Long operation times increase patient risk and potential problemsrelated to such procedures. These problems include for instanceincreased risk for clots occurring during the operation. Also, longoperation time implies long times of X-Ray use, which both the operatorand the patient are exposed to. Moreover, contrast media is then used inlarge amounts.

It is therefore also desired to reduce the X-Ray dosage both for thepatient and operator. Shorter scanning times or less positions scannedas well as reduced use of contrast agent that needs to be injected intothe patient’s blood is desired. There is therefore a need to reduce timeneeded for such implantation procedure, both for reduction of radiationexposure of primary radiation of the patient and secondary radiation(scattered radiation) of the operator. It would be advantageous toprovide a covered stent, covered stent system, or procedure tofacilitate a diminished scanning time. Examples of the inventiondescribed below provide this advantage as described below.

A further undesired issue with the known art is that implantation of acovered stent implant, in particular longer endoprosthesis systems ofsuch covered stents covering multiple side branch vessels, is acomplicated operation.

In known endoprosthesis the covered stents need to be assembled in asingle deployment of the covered stent system. Should for instance sidebranch vessel openings of a main covered stent be positioned wronglyupon deployment in relation to the side vessel, re-positioning of themain (vessel) stent is very difficult or impossible. The prior artsystems allow for no flexibility or very little tolerance upondeployment regarding mal-positioning of a main stent in relation to sidevessels. Flexibility of reaching side vessels with such stent isdesired.

Re-positioning of further parts of a stent graft system in relation toside vessels should be advantageously provided and the deploymentprocedure be facilitated. Hence, a novel covered stent, covered stentsystem or implantation procedure is desired to allow for individualpositioning of one or more side vessel stent grafts. Examples of theinvention described below provide this advantage as described in moredetail below.

The minimal invasive implantation of an endoprosthesis requires hithertocontinuous fluoroscopic scanning by X-Ray so that the operator can seewhere and how to position the different covered stent modules in apatient’s vascular system for assembling the endoprosthesis inside thepatient.

Frequent change of scan angles of the X-Ray modality is required toenable the operator to find branch vessels in three dimensions and therelation of covered stents to apertures of a covered stent module in amain vessel. The scan techniques used for this only enables the operatorto see the scanned body in one plane at a time only, i.e. in twodimensions, one layer at a time.

Three dimensional visualization of branch vessels location and orificesin relation to apertures of a covered stent requires repeatedly moving afluoroscopy scanner arm from one plane to another plane and then movingit back again to the first plane. This is needed to ensure alignment inthree dimensions between the covered stent in the main vessel and theside branch vessel. It is important that the components are placed in acorrect position at the implantation site in the patient.

With multiple apertures and side branch vessel connections to be alignedfor one single covered stent in the main vessel, this task becomesparticularly complicated.

There is therefore a need to make the assembly less complicated. Thedisclosure of examples of the invention found below advantageouslyprovides a less complicated assembly of covered stents. Reduced X-raytimes and related radiation dosages would be advantageous for bothpatients and clinical personnel.

Thus, there is a need for a medical device and/or system, or medicalprocedures that are safer, avoiding the aforementioned drawbacks ofknown systems and procedures. Preferably a device and/or system ormethod is desired that makes the operation times shorter. Procedures aredesired to be more easily performed by the operator. Simplifiedimplantation procedure is desired. Complication rate is desired to bereduced. Novel medical procedures with reduced patient risk are desired.Simpler implantation is desired. Medical procedures are desired, whichcan be performed despite the fact that they would be avoided today in arisk assessment of patients. For instance as known stent systems wouldhave implied too high risk for complications and open chest surgery isno option for many patients, in particular elderly patients), suchsimplified implantation, or devices facilitating simplifiedimplantation, are desired. Less X-ray dosage needed during the procedureis also desired. Hence, there is a desire to be able to provide novelmedical procedures, implying reduced patient risk.

SUMMARY OF THE INVENTION

Accordingly, examples of the present disclosure preferably seek tomitigate, alleviate or eliminate one or more deficiencies, disadvantagesor issues in the art, such as the above-identified, singly or in anycombination by providing medical devices, systems, and methods accordingto the appended independent patent claims.

The present novel covered stent system allows, amongst others, forindividual, single delivery of side vessel stent branches. This reducestotal operation time considerably. Also, patient safety is improved astime is reduced and/or other side vessels still are perfused when oneside vessel stent is deployed by the operator.

The novel system allows for novel medical procedures, which today wouldimply too high risk for the patient. Thanks to the more simpleimplantation, medical procedures can be performed which were avoidedtoday in a risk assessment of patients - for instance as known stentsystems would have implied too high risk for complications and openchest surgery is no option for many patients, in particular elderlypatients.

Examples of the invention described below allow advantageously reducingtime for part of or an entire procedure. Implantation time is shortenedcompared to the prior art systems, and thus for instance the total doseis advantageously reduced. The angle of the x-ray modality needs to bechanged less often than required by the prior art systems. Less amountof contrast medium is needed. Over all the below disclosure provides forreducing potential side effects for the patient. Moreover, the cost ofthe procedure will be reduced.

The covered stents discussed herein are in an example self-expanding, orin another example expandable by another device, such as an inflatableballoon.

According to a first example, a medical device is provided. The deviceis a covered stent having a main body, and at least one lateral sidebranch connected to the main body. The lateral side branch is flexibleand expandable.

According to an aspect of the disclosure, a system is provided.

The device and/or system may be used in medical procedures and methodsas described herein.

Aspects of the disclosure include, but are not limited to the following.

-   In a first aspect, a covered stent is provided having a main body,    and at least one branch, including one, two or three branches,    connected to the main body. The covered stent also includes at least    one bendable and/or flexible guiding element being distally    permanently or releasably attached to an interior of one of the at    least one the branches at a connection point, preferably at a distal    orifice of the branch. The guiding element is proximally arranged in    the interior, through and along a proximal portion of the main body    and extends proximally through a proximal opening of the main body.    In this manner a catheter can be guided over the guiding element    through the main body towards the distal orifice of the branch.-   In a second, a delivery catheter is provided for delivery of a    second covered stent to be connected to a first covered stent. The    catheter has a delivery lumen with a distal orifice for delivery and    deployment of the second covered stent at a target site of a branch    of the first covered stent. The catheter further has a guiding mate    for receiving a guiding element distally attached to a connection    point at the branch. In this manner the catheter can slide along the    guiding element over the guiding mate to the orifice of the branch    and the delivery and deployment of the second covered stent through    the delivery lumen of the catheter. The guiding mate for receiving    the guiding element has preferably a distal end positioned    proximally at a distance from the distal orifice of the delivery    lumen such that the delivery lumen extends beyond the connection    point when the guiding mate distal end engages the connection point.-   A modular system of a covered stent according to the first aspect    and a delivery catheter of the second aspect with the guiding    element arranged through the guiding mate for delivery of a second    stent graft through the delivery catheter to the target site of the    branch. The second stent graft preferably is an extension stent    graft.-   A modular covered stent system including a plurality of covered    stents, wherein at least one of the covered stents preferably is a    covered stent of the first aspect of the disclosure. The plurality    of covered stents are configured to be inter-connectable to each    other. The plurality of covered stents includes a first main vessel    covered stent with a first single distal upstream inlet branched    into at least two proximal downstream outlet branches, and at least    two covered stents with at least one lateral side branch orifice.    Each of the at least two covered stents is distally interconnectable    to one of the downstream outlet branches of the first main vessel    covered stent and laterally connectable to a side stream vessel of    the main vessel. The at least two covered stents can be sequentially    interconnected to one of the downstream outlets branches for    providing blood conduits arranged in parallel by the at least two    covered stents. The modular system includes a second main vessel    covered stent with at least two distal upstream inlet branches    collected in a single proximal downstream outlet, each of the distal    inlet branches to be interconnected to a proximal outlet of one of    the at least two covered stents.-   A method for navigating a covered stent to a vascular target site,    including providing a covered stent of the first aspect of the    disclosure. Further the method includes delivering the covered stent    to a vascular target site, and navigating a branch of the covered    stent into or towards a branch vessel. The method includes providing    a catheter according to the second aspect of the disclosure and    arranging a guiding element attached to the covered stent through a    guiding mate of the catheter, advancing the catheter along the    guiding mate until an attachment point of it stops further    advancing. The method includes delivering a second stent graft or a    guidewire thereof through a lumen of the delivery catheter to a    target site of the branch of the covered stent, the second stent    graft preferably being an extension stent graft. The method    optionally includes affixing the extension stent graft proximally to    the branch and distally in the branch vessel.-   A medical procedure including accessing a target site being a vessel    in a patient and delivering a first covered stent to the inside of    the vessel at the target site through a delivery catheter. The    target site has a side branch vessel and the method includes    delivering a second covered stent to the first covered stent and    connecting the first covered stent to the second covered stent for    providing a blood flow to the side branch vessel. The delivery of    the second covered stent includes sliding a catheter along a guiding    element to a position inside a lumen of a side branch of the first    covered stent. The method may include expanding the second covered    stent for connecting to the first covered stent.-   A medical procedure including accessing a target site being a vessel    in a patient and delivering a first covered stent to the inside of    the vessel at the target site through a delivery catheter. The    target site has a side branch vessel and the method includes    expanding the side branch and delivering a second covered stent to    the first covered stent and through the side branch to the side    vessel. The method includes connecting the first covered stent to    the second covered stent for providing a blood flow to the side    branch vessel.-   A medical procedure for aortic vessel reconstruction including    delivering covered stent modules are delivered in a specific order.    The method may start with implanting a three-legged covered stent in    the ascending aortic arch. The method includes delivering, in    downstream direction of the aorta, two parallel covered stents with    one side branch each, in the aortic arch, and sequentially    connecting the parallel covered stents to a leg of the three-legged    covered stent and a branch vessel of the aortic arch. The method    includes delivering, downstream the aorta a covered stent collecting    the parallel covered stents. For instance the collecting includes    providing two distal legs united into a single lumen body having a    proximal orifice, connecting the two distal legs to a proximal end    of one of the two parallel stents, respectively. Different number of    parallel covered stents than two changes the number of legs    accordingly. Intermediate collection numbers of legs may be provided    by devices, systems and methods.

Further examples of the disclosure are defined in the dependent claims,wherein features for the second and subsequent aspects of the disclosureare as for the first aspect mutatis mutandis.

Some examples of the disclosure provide for an improved navigation ofand assembling of a covered stent or a plurality of covered stents, eachin a side branch vessel from a main vessel.

Using this innovative system, device and/or method, an operation toposition a covered stent with side branch connections, in particularwith multiple side vessels (up to four side branches) such with forexample three or four side branches, the time needed for implantation isexpected to be considerably reduced, in the range of several hours lessthan conventionally would have been needed. Using conventionalpre-fabricated stent grafts, such a procedure takes instead much longertime, around 10 hours operation time or longer. Despite the enormousreduction of surgery time for positioning the covered stentdevice/system, no safety of procedure is lost. Instead safety may beimproved. The delivery of the innovative device and system is veryreliable. Time for implantation is significantly reduced by the novelmodular system and/or its components and/or the procedure forimplantation possible by the system’s features. This is described indetail below.

By covered stent means a stent having a liner, shell or being otherwisesurrounded by a liquid impermeable fabric or material. The covered stentcan be partly or fully covered. A covered stent can also be called astent graft or an endoprosthesis.

A side branch 3 may be laterally extendable and/or collapsible, i.e.expandable in a direction of a longitudinal axis along the side branch3, which direction is preferably substantially perpendicular to alongitudinal axis along a main body 2 of a covered stent 1.Alternatively, or in addition, the side branch 3 may be expandable in atransverse direction, i.e. expandable transverse to the direction of anaxis along the side branch 3. The side branch 3 may comprise a coveredstent and may in some examples be a covered stent.

In examples, the side branch 3 is about 1 cm to 1.5 cm laterallyextendable.

The side branch 3 is in an example integral with the main body 2, eitherby the covered stent of the main body 2 and the covered stent of theside branch 3 being integral, or by the cover of the main body 2 and thecover of the side branch 3 being integral. In an example both cover andcovered stent of the main body 2 is integral with the cover and coveredstent of the side branch 3. When the side branch 3 comprises the coveredstent it is stiffer and can then resist more handling when e.g.deploying and/or re-deploying any further covered extension coveredstent. This also allows for the side branch 3 to form a tighterconnection with any further covered extension covered stent out from theside branch 3.

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps or components but does not preclude thepresence or addition of one or more other features, integers, steps,components or groups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fee.

These and other aspects, features and advantages of which examples ofthe disclosure are capable of will be apparent and elucidated from thefollowing description of examples of the present disclosure, referencebeing made to the accompanying drawings, in which

FIG. 1 is a schematic illustration that shows a system of differentcovered stent modules for implantation inside the aortic arch andthoracic aorta of a patient;

FIG. 2 is a schematic illustration that shows the system of FIG. 1 whenit has been implanted inside the aorta of a patient;

FIG. 3 is a schematic illustration of a covered stent with three legs,and a navigation element and a suture for easy navigation to all threelegs;

FIG. 4 is a schematic illustration of a covered stent with a sidebranch;

FIGS. 5 a-b are a schematic illustrations of two examples of a coveredstent with more than one side branch;

FIG. 6 is a schematic illustration of, bottom-top, one example of a sidebranch which is self-expandable from a collapsed to an expanded shape;

FIG. 7 is a schematic illustration of a covered stent with a folded orcollapsed side branch be used to locate a branch vessel;

FIG. 8 is a schematic illustration of a covered stent with a sidebranch, and a catheter with a guiding mate for guiding the catheter foreasy navigation of the side branch;

FIGS. 9 a-c is a schematic illustration of a restraining member and acovered stent being self-expandable from a collapsed to an expandedshape by removal of the restraining member;

FIG. 10 is a schematic illustration of a sheath used to hold the coveredstent in a collapsed or folded manner, and to controllably release thecovered stent, partially or fully;

FIG. 11 is a schematic illustration of a covered stent before and afterthe covered stent is fully expanded;

FIG. 12 is a flow chart of an example of a medical procedure;

FIG. 13 is a flow chart of an example of a method for navigating acovered stent to a branch vessel;

FIGS. 14A-D are a perspective view, a top view, a lateral view and afront view of an example of a modular covered stent 300 with a singlelateral side branch;

FIG. 15A is a perspective and sectional view (upper part of figure) of amodular covered stent 300 with a lateral side branch in a deliveryconfiguration in a perspective view (lower part of figure):

FIGS. 15B and 15C are schematic views of deployment of the lateral sidebranch of the modular covered stent 300 of FIG. 15A before release ofthe main body;

FIG. 16 is a cross sectional view of a double lumen delivery catheter;

FIG. 17A is a perspective and sectional view of a modular covered stent300 with a lateral side branch in another delivery configuration;

FIG. 17B is a schematic view of a release of a main body and lateralside branch of the modular covered stent 300;

FIG. 18 is a schematic view of a catheter tool for releasing anavigation unit from an extension of a lateral side branch; and

FIGS. 19A, B and 20 are schematic illustrations of different stentpatterns of a lateral side branch.

DESCRIPTION OF PREFERRED EMBODIMENTS

Specific examples of the disclosure will now be described with referenceto the accompanying drawings. This disclosure may, however, be embodiedin many different forms and should not be construed as limited to theexamples set forth herein; rather, these examples are provided so thatthis disclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. The terminologyused in the detailed description of the examples illustrated in theaccompanying drawings is not intended to be limiting of the disclosure.In the drawings, like numbers refer to like elements.

The following description focuses on an example of the presentdisclosure applicable to a medical device and in particular to a medicaldevice for facilitating navigation of and assembling of a covered stentor a plurality of covered stents in communication with at least a sidebranch vessel. The implant can be used for treatment and/or repair ofvascular disease, such as e.g. aneurysm. The example is illustrated withan arrangement in the aorta. The vessel like the aorta may bestructurally damaged of different reasons and need repair along at leasta portion of the aorta 500. Sometimes extensive endoprosthesis areneeded for aortic repair, partly or all the way from the ascending aorta501 via the aortic arch 502 down the descending aorta 503 and along theabdominal aorta 504 past the renal arteries 505.

An example of such an endoprosthesis including modular embodiments andassembly is illustrated in FIGS. 1 and 2 and the corresponding textherein. Total aortic reconstruction or repair can be provided whenimplanting the entire system as shown in FIG. 2 . Partial aorticreconstruction or repair may be provided with selected sub-modules ofthe system being implanted only. However, other anatomical structuresmay be provided for treatment with the devices and/or systems of thedisclosure, including abdominal covered stents, peripheral stent grafts,endoluminal prosthesis, and include e.g. but not limited to peripheralveins, leg arteries, spinal vessels, neuro structures, lymphatic system,etc.

FIGS. 1 and 2 show a system of various covered stent modules 200, 300,310, 320, 400, 410, 420, 430, 600 for implantation inside the aorticarch 502 and abdominal aorta 504 of a patient. FIG. 2 shows the system100 of FIG. 1 when it has been implanted inside the aorta 500 of apatient and the modules being connected to each other. Further extensionstent grafts 600 not shown in FIG. 1 are connected and shown in FIG. 2 .A reliable communication of blood is provided through the prosthesis ina main vessel, here the aorta 500, and into branch vessels, here to neckvessels, renal arteries 505 and others. The aortic wall is in theexample illustrated with weakenings/aneurysms in the descending aorticarch and abdominal aorta, needing treatment provided by the exemplarystent graft system 100 for aortic replacement/repair.

In the illustrated example, a number of covered stents 1 (reference sign“1” cited together in this specification can be regarded a placeholderfor “covered stent” or “covered stents”, e.g. of the types disclosedherein, as for instance covered stents 200, 300, 310, 320, 400, 410,420, 430, 600 etc.) is assembled and interconnected to fit inside partsof, or the entire, aorta of a patient to form a system 100 or a modularsub-system thereof. The covered stents 1 discussed herein may also beimplantable in other target sites of the body for repairing and/orre-building conduits of vessels for liquid communication through thevessels.

FIG. 1 illustrates different kinds of modular covered stents 1 that canbe used for an exemplary assembly of the system 100 of modular coveredstents 1 that fit inside the vessels of and around the aortic arch 502of a patient. The system 100 may be assembled in vivo or in vitro.

Alternatively, systems may include more or fewer covered stent modules.For instance, only the aortic arch may be covered by modules likecovered stents 200, 300, 310, 320, 400, 410 - all depending on thetreatment site and treatment needs. Other examples of combination ofcovered stent modules are: a) 200, 2×300 + 2×600, 400 and optionally 600in 201; b) 420, 310 + optionally 2×600, 320 + optionally 2×600, and 430;c) intermediate 410 + example a) and b); etc.

Some of the covered stents 1 have side branches 3 that are provided toextend blood communication through the system, and preferably intobranch vessels. Examples of such covered stents are modular coveredstents 300, 310, 320.

Some of the covered stents 1 have legs, i.e. the main body 2 of thecovered stent 1 branches into two or more tubular parts. Examples ofsuch covered stents are modular covered stents 200, 400, 420, 430.

Alternatively, or in addition, and although not shown in the figures, acovered stent 1 may have both side branches 3 and legs. Covered stent200 might be considered an example having two legs 202, 203 and a sidebranch 201. Both legs and side branches can be considered being branchesin the present context. Other covered stents, not discussed or shownherein but commonly used today may also be used in the system 100.

The modular covered stent system 100 comprises a plurality of coveredstents 1, wherein at least one of the covered stents is a covered stent1. The plurality of covered stents 1 are configured to beinter-connectable to each other.

Alternatively, or in addition, the system further comprises an elongatednavigation element 20, which allows the operator to navigate the coveredstent and/or the side branch 3 of the covered stent 1 and align the sidebranch 3 with branch vessels. The elongated navigation element 20 ispreferably a guide wire, such as shown in FIG. 1 .

In an example, the covered stents have a substantially identicaldiameter at an inter-connection between two covered stents to provide aliquid tight interconnection.

In an example, having the same diameter at an inter-connection meansthat the outer diameter at the inter-connection of one of the coveredstents is substantially the same as the inner diameter at theinter-connection of the other covered stent, at least along a portion ofthe covered stent. The same diameter is maintained at least along anoverlapping portion of the two covered stents, if overlapping. The twocovered stents are thus for instance liquid conveying connectable byoverlapping each other and one tube inside the other connected tube.

The stent structure of covered stents is part of the covered stent. Itmay have a pattern, like undulations. The pattern may be made by made bybraiding, weaving, laser cutting of a tube, etc. The structure is ascaffold to support the structure outwards and provide a substantiallytubular structure to ensure undisturbed blood flow through the tube whenimplanted as it is provided with and covered by a suitable liquid tightcover.

The undulations or pattern can be denser at the overlapping connectionregion than other regions of the covered stent -for a secure liquidtight connection of two covered stents and by improved mechanicalstrength.

FIGS. 19A, B and 20 are schematic illustrations of some exemplary stentpatterns / undulations of a lateral side branch.

The pattern in FIG. 19A shows a wavy (nitinol) wire or laser cutstructure that is easy to reduce its outer diameter and to fold it downbeside the prosthesis main body into a delivery configuration. Uponrelease from a catheter or removal of a restraining member, it willresiliently expand longitudinally, as will the designs of FIG. 19B andFIG. 20 .

The pattern in FIG. 19AB has a region without a supporting frame in thezone 3 b that the extension prosthesis 600 will overlap with. The framepattern has an asymmetrical design. The dotted line 3 c in the Figureindicates an area that will encourage the stent to collapse. This designrequires less force to fold and less space to store it for delivery inan outer sheath. The portion with a longer support frame (in the left ofthe Figure will ensure the side branch prosthesis is expanded in asufficient length which will stay in the side branch or be orientedradially outwards from the main body.

The pattern in FIG. 20 shows two halves of a frame pattern that willadvantageously collapse to the middle. Also this design requires lessforce to fold and requires less space to store it for delivery in anouter sheath.

The collapse of side branch 3 for delivery through a catheter may beobtained in multiple ways. It may be folded back, slid sideways alongthe catheter inner lumen, or compressed along its longitudinal axis. Ifa cover is provided (FIG. 9 etc.) the side branch, and covered stent,are collapsed and held inside the cover / restraining member 8. Therestraining member 8 may be of a material with low friction, such asPTFE. The restraining member 8 allows for a pull/push release of acovered stent contained in the restraining member 8 during deliveryuntil deployment. Alternatively, or in addition, the inside of thecatheter may be provided with a good sliding property material tofacilitate movement of the covered stent along the inner lumen to thetarget site, with the restraining member optionally covering the coveredstent during delivery until final deployment.

In another example having the same diameter means that the two coveredstents to be connected have substantially the same inner diameter at theinter-connection and are connected in a non-overlapping manner, e.g. endto end connected. An additional inner liner may be provided at theconnection site of the two covered stents, preferably downstreamentering the inner of the downstream oriented covered stent from theupstream positioned covered stent.

In an example the two covered stents to be interconnected have bothsubstantially the same inner diameter and substantially the same outerdiameter at the interconnection, and the covered stents are connected byoverlapping them when one of the covered stents is in a partiallycollapsed or folded state.

Having covered stents with the same or substantially the same diametermakes it easy for the operator to connect the various covered stentssince the diameter of corresponding covered stent parts of the system100 is similar and the operator does then not need to worry about anyparticular connection method, stent shape, connection site or the like.This means that the operator does only need to consider if the previouscovered stent were a single, double, triple or further legged coveredstent. This also makes the production of the covered stents easier sincethe diameter at the connection of the various covered stents are thesame. An example is the diameter of legs 202, 203, covered stent 300main body, and upstream oriented legs of the covered stent 400.

The overlapping region allows for length adaptation of the modularsystem. For instance the modular covered stents, 400, 410, 420 could beprovided as a single integral unit. However, providing straight middlepiece covered stent 410 separate from branched end piece covered stents400, 420, allows for adjustment to specific patient anatomy (in theexample different length of abdominal aorta). Overlap of the middlecovered stent can be varied accordingly. Length adjustment of a systemof modular covered stents is provided by an overlapping portion atopenings of covered stents allowing for varying overlap and determiningtotal length of the assembled modular system upon implantation. Thisapplies, mutatis mutandis to side vessel extension covered stents 600connections, etc.

In the prior art, systems of covered stent modules are provided withcovered stents that have a varying diameter in e.g. a tapered shape.They are connected by inserting a first folded tapered shaped coveredstent into a second expanded tapered shaped covered stent. When thefirst covered stent is expanded, the two covered stents form aconnection. Such a system causes an unnecessary additional task for theoperator to keep track of in addition to keeping track of all thecovered stent modules not only being in the right order, in the rightdirection before and during the entire operation but also need to keeptrack of where and how these two cones fit to each other. In contrary,examples of the present disclosure provide for a simpler, safer andquicker procedure of implantation.

Providing the covered stents 1 with substantially the same diametergives the advantage that the operator can implant each covered stent 1as explained above, or in an example in any direction he or she thinksis best. This will shorten the time required for assembling the system100 and consequently the operation, drastically.

In an example, when the covered stent 1 has substantially the samediameter as discussed above and is expanded, or when a side branch 3 orleg of the covered stent 1 is expanded, a flow through the covered stent1 is more or less unchanged through it. Meaning that a liquid, such asblood, entering at one side e.g. the main body 2 will pass through thecovered stent 1 and out through e.g. two legs at the other side and dueto the expansion and same diameter of connection at the covered stents 1an inlet and outlet area are substantially the same. This allows theoperator to concentrate on connecting one covered stent 1 or part of acovered stent 1, such as a leg, at the time. The operator needs not toworry about the covered stent 1 disturbing the flow or throughput in thecovered stent 1 or vessel.

Additionally, this allows for using a covered stent or a plurality ofcovered stents in a system and assembly at the implantation target site,i.e. not premanufactured for a specific patient. This is an advantageover known systems. Known systems included hitherto pre-built, patientspecific endoprosthesis. Usually, an image modality is used to scan thevessel system including the target site, e.g. a weakened aorta, earlierin time. The endoprosthesis is then manufactured based on the imagingdata and delivered to the surgeon for implantation. This manufacturingof a patient specific endoprosthesis usually takes days to weeks, whichis undesired. The anatomy of the vessel may change during this waitingtime. The consequence may be that the manufactured endoprosthesis doesnot fit the patient anymore. Also, the waiting time is undesired as thepatient mostly is in immediate need of the endoprosthesis, e.g. to avoidrupture of an aortic aneurysm. If desired, however, specific embodimentsof the covered stents of the present disclosure may be manufacturedpatient specifically. A standard setup of different sizes readilyavailable for implantation is preferred, though, as waiting time due tomanufacturing is avoided.

The modular covered stent system 100 may further comprise a guidingelement 10, like a suture or wire. Along guiding element 10 a deliverycatheter may be threaded proximally to the distal end of the guidingelement 10. The guiding element 10 is distally affixed to a coveredstent, for instance a suture may be affixed by means of a knot, staple,weld, adhesive, or similar. The guiding element 10 is thus secured tothe covered stent. Preferably, the attachment point where the guidingelement 10 is distally secured to the covered stent is at the interior,e.g. at a location of a lateral side branch of the covered stent. Theguiding element 10 is preferably pre-loaded in a delivery catheter ofthe covered stent. The guiding element is in use operating as a guilderfor a guiding mate 9 of a catheter. The guiding element 10 is preferablybendable and/or flexible. bendable and/or flexible.

In embodiments, the guiding element 10 is thus distally permanently orreleasably attached to an interior of a branch, e.g. a lateral sidebranch, at a connection point, preferably at a distal orifice of thebranch 3. The guiding element 10 is proximally arranged in the interior,through and along a proximal portion of the main body 2 or another ofthe branches 3 and extending proximally through a proximal opening ofthe main body 2 (see e.g. FIGS. 3 or 8 ). In use the guiding element isthus operating for guiding a catheter over the guiding element 10through the main body 3 towards the distal orifice of the lateral sidebranch 3.

See FIGS. 3 or 8 and the corresponding text below for more detaileddescribed examples of the guiding element 10 and its corresponding useand application in a modular stent graft system.

Alternatively, or in addition, a guiding element 10 can be distallyattached to the aorta of a patient at a desired target location.

Alternatively, or in addition, the attachment of a guiding element atits distal end may be releasable, preferably releasable from outside thebody activation, for removing the guiding element during theimplantation procedure, as needed. A knot may be releasable, thermaldetachment means may be provided for controlled detachment of theguiding element at the attachment point. Alternatively, or in addition,the guide element may be configured to be cut off after use. Suitabletools may be used for the cutting off, e.g. a sheath with an interiorsecure cutter slid over and along the guiding element towards theattachment point, where the cutter is activated and the guiding elementcut off. The guiding element may then be securely retracted out of thebody, e.g. within the sheath having the cutter, or just proximally drawnout of the vasculature via the puncture site / introducer.

However, the guiding element 10 is preferably left in place uponconcluded implantation procedure. The guiding element 10 can be left inplace after use (guiding delivery and deployment of e.g. an extensionstent graft). It may be made of a biodegradable material orbioabsorbable material. The guiding element 10 is in any case made of abiocompatible material, including absorbables such as polyglycolic acid,polylactic acid, Monocryl and polydioxanone as well as thenon-absorbables nylon, polyester, PVDF and polypropylene, PTFE orDacron. The guiding element 10 may be made of metallic material, such asNitinol or stainless steel, or a suitable metal alloy, which might beadvantageous from a durability advantage during implantation. This isadvantageous when the guiding element is left in place after concludedimplantation procedure of the modular covered stent system. Theprocedure can be shortened as the guiding element needs not to bedetached or cut off at or close to the connection point. It may be cutof at is proximal end only, or not at all.

Along guiding element 10, the delivery catheter 30 may be moved towardsthe distal end of the guiding element 10, e.g. by means of a guidingmate 9 on the catheter as described below (FIG. 8 ). Delivery of anotherelement, device or unit, can then take place through this deliverycatheter to a desired site at the distal end of the guiding element 10.X-Ray guidance, probing, navigation tries etc. can advantageously bereduced or omitted.

In this manner, a catheter can be moved along the guiding element to ortowards the distal end thereof without fluoroscopic guidance. In thismanner, reliably, and speed of delivery is improved while radiationexposure can be reduced.

Such a delivery catheter 30 is provided for delivery of an extensionstent graft 600. The catheter 30 has a delivery lumen with a distalorifice for delivery and deployment of the extension stent graft 600 ata target site of a lateral side branch 3 of a covered stent 1.

The catheter 30 further has a guiding mate 9 for receiving a guidingelement 10 distally attached to a connection point at the branch 3.Therefore, the catheter 30 is configured to slide along the guidingelement 10 over the guiding mate 9 to the orifice of the branch fordeployment of the element, such as the extension stent graft 600 throughthe delivery lumen of the catheter.

The guiding mate 9 for receiving the guiding element has a distal endpositioned proximally at a distance from the distal orifice of thedelivery lumen. In this manner the delivery lumen extends beyond theconnection point when the guiding mate 9 distal end engages theconnection point.

As can be seen e.g. in FIG. 8 , the distal end of the delivery catheter30 may be pre-bent to advantageously enter into the side vessel from thebranch orifice. In this manner the operation time is reduced,fluoroscopic load of the patient and clinical personnel reduced, and theimplantation made more securely and reliable.

A modular stent graft system is provided including a covered stent 1 anda delivery catheter 30 with a guiding element 10 arrangeable or arrangedthrough a guiding mate 9. In this manner a unit, such as an extensionstent graft 600 is advantageously deliverable through the deliverycatheter 30 to a target site at a branch 3.

In addition, the distal end of the guiding element 10 is for examplearranged at a marker 21. Alternatively, or in addition, the guidingelement 10 may be provided itself with a marker. Marker means fiducialmarker that is visualizable by suitable imaging means for the surgeonperforming the implantation procedure. The marker 21 is preferablyarranged at a leg 4 of a covered stent for guiding delivery of anothercovered stent towards and/or through the distal orifice of such a leg 4,e.g. as described below, to a side branch vessel of a main vessel. Themarker may be elongate and extend along at least a part of the length ofthe guiding element 10, e.g. as a radiopaque strand of a multi-strandwire/suture/thread, and/or one or more marker bands.

To make it easier to position another covered stent in relation to a legof a first covered stent the marker 21 is provided at e.g. the leg ofthe first covered stent. In the same way a marker 21 may be provided onthe side branch 3 of a covered stent 1, allowing easier aligning of thecovered stent 1 in relation to a branch vessel. X-Ray may then be usedfor position confirmation, which means a reduction of dosage compared tofull X-Ray supported navigation with contrast medium.

The illustrated modular covered stent system 100 includes a first mainvessel covered stent 200, 420 with a first upstream inlet branched intoat least two downstream outlet branches.

Further it includes a covered stent type 300, 310, 320 that has a mainbody, and at least one lateral side branch connected to the main body.The lateral side branch is preferably flexible and expandable. Thecovered stent is interconnectable to one of the downstream outletbranches and laterally connectable to a side stream vessel of the mainvessel via the lateral side branch thereof. At least two covered stents300, 310, 320 are thus sequentially interconnectable to one of thedownstream outlets of the main vessel covered stent 200. In this manner,blood conduits are provided arranged in parallel by the at least twocovered stents, one at a time assembled by the operator. The parallelblood conduits may be provided with one or more side branches each.Alternatively, or in addition, a blood conduit in form of a coveredstent may be provided that has no lateral side branch, which thenprovides a straight blood flow path in parallel with e.g. a coveredstent having one or more lateral side branches.

The parallel arrangement of covered stents has several advantages.Repositioning of one of several parallel covered stents is more easilyperformed than that of a single covered stent covering the entire vesselwith multiple side branches. It is easier to sequentially implantseveral parallel covered stents with one or few branches than one largecovered stent with many branches. The proximal and distal ends of thecovered stent 300, 310, 320 are not stented into vessel tissue wall.Mechanical stability and attachment are thus better controllable than inrelation to an anatomical structure, in particular if this is weakenedsuch as at an aneurysm. As the parallel covered stents 300, 310, 320 canaccommodate movements of the vessels better, this is an advantage. Thereis less risk of damaging the tissue vessel as contact is reduced, whichpositively affects long term implantation stability of the modularsystem. Adaptation to anatomy at implantation is made easily by thesurgeon as rotation and longitudinal position are adjustable intraoperatively. No aortic clamping is needed and cardioplegia is avoided,which reduced side effects for the patient and makes the procedurequicker, and reduced patient risk. As each of the parallel coveredstents 300, 301, 320 has a lesser diameter than the vessel into whichthey are implanted, a distance to side branches from the covered stentmain lumen is provideable. This in turn allows for navigational space ofthe covered stent in relation to a side branch vessel orifice.Positioning of the side branch of the covered stent in relation to theorifice is thus less critical than for known systems. Compensation canbe made thanks to the distance between the side branch of the coveredstent and the orifice of the side vessel’s orifice, e.g. by bending aside branch and/or by bending an extension covered stent 600 withoutkinking one or both of the latter mentioned when implanted from the mainvessel into the side vessel.

The modular covered stent system further includes a second type of mainvessel covered stent 400, 430 with at least two upstream inlet branchescollected in a downstream outlet. The inlet branches areinterconnectable to a distal outlet of one of the two covered stents,e.g. covered stents type 300, 310, 320 as shown in FIGS. 1 and 2 .

Starting from the top of the system 100 as illustrated in FIGS. 1-2 ,there is illustrated a first covered stent 200 with three legs. Thismodule is implanted firstly over a guidewire 20.

It should be noted that the covered stent modules are delivered in aspecific order, starting with a three-legged covered stent 200 in theascending aortic arch. Further covered stent modules are then deliveredto the target site until the entire system is implanted. This is done ina very efficient and advantageous manner.

For instance, when the three legged covered stent 200 is deployed andimplanted firstly of all modules in the ascending aortic arch. This canbe done via a guide wire 20, e.g. in a femoral access approach. Furthercomponents can then be connected to the legs 201, 202, and/or 203.

For instance a covered stent 600 can be delivered to the first leg 201via a delivery catheter slid along guiding element 10 to or towardsconnection point 11, such as in the manner described with reference toFIG. 8 . This covered stent 600 can then extend blood flow into thefirst neck side vessel as shown in FIG. 2 . The covered stent 600 is acovered stent without apertures for side vessels. The extension stentgraft 600 is configured to be proximally matingly and fluid tightconnected to the distal portion at the orifice of the first leg 201.Connection may be done overlappingly in a suitable manner and bysuitable means known in the art of connecting stent grafts to each otherfor providing a communication channel for liquid there through to thetarget vessel.

Delivery is thus provideable in two steps. Firstly, the side branch 3 isexpanded. Then a side vessel covered stent 600 is deployed through theexpanded side branch 3. Fixation of the side vessel covered stent 600 isdone then. The entire prosthesis is flexible until the side branch isfinally intubated, i.e. the side branch covered stent 60 is deployed andthus “locked” in position.

During delivery of covered stent 600, the two remaining legs 202, 203are not obstructed and blood flow through the aortic arch is ensuredduring the implantation procedure, which is an important advantage.

The guiding element 10 is also running inside the third leg 203. Thismeans, that over same guiding element 10 and delivery catheter overwhich the covered stent 600 was delivered, the covered stent 300 with aside branch is deliverable.

The initial guidewire 20 for delivering the three-legged covered stent200 to its target site, is used for delivering and connecting a coveredstent 300 to the second leg 202.

The location of three-legged covered stent 200 is preferably marked witha fiducial marker 21 that can be seen during imaging by e.g. MRI, CT orX-ray. Hence, shortened radiation times and dosages are provideable.

As the guiding element 10 extends out from the first leg 201, all threelegs can be located and modular covered stents interconnected at theorifices of the three legs. No additional navigation, searching orprobing by the surgeon is needed, thus reducing radiation times anddosages.

The guiding elements 10 are for guiding subsequent covered stents alongthem so that the subsequent covered stents can be connected to apreviously implanted covered stent.

In addition, or alternatively a navigation element 20, such as a guidewire, is used instead for or together with one or more guidingelement(s) 10 in the system 100 for guiding all or almost all of thecovered stents of the system 100 to their target site.

Next, the system 100 includes in proximal direction, downstream theaorta, two covered stents 300 with one side branch each, positioned inthe aortic arch 502 upon implantation. The two covered stents 300 areeach guided by the guiding elements 10 and guidewire 20, respectively.These modular covered stents 300 are described in more detail below,e.g. with reference to FIGS. 5 a, 6, 7, 8, 10, 11, 14, 15, 17, 19 and 20. Each of covered stents 300 is distally connected to a leg 202, 203 ofthe three legged covered stent 200. The side branch exit is preferablyexpandable, and in liquid communication with a neck vessel whenexpanded. A further covered stent 600 is further connected with itsproximal end, respectively, extending into the remaining two neckvessels respectively (see FIG. 2 ). Delivery of these further coveredstents 600 can be done fiducial marker guided (not shown), withguidewires and contrast medium feedback, and/or a guiding element 10 canbe connected to the branch (see FIG. 8 ) facilitating delivery of thefurther covered stents 600 through the orifice of the side branch ofcovered stent 300 and into the respectively neck vessel.

Delivery of each covered stent 300 and extension is done sequentially.While delivering the first of these two units 300, the other leg ofthree-legged stent 200 is not obstructed and blood flow through theaorta ensured. Also, when delivering the extension into a neck vessel,blood flow both downstream the aorta and into the neck vessel isuninterrupted during the procedure.

When both covered stents 300 are interconnected and delivered, aparallel flow through the aorta is provided with sufficient blood flowneeded due to a high ratio of lumen diameter to (healthy) aortadiameter.

As the orifices of the lateral branches can be located at a distancefrom the ostia of a target site vessel thanks to the parallelarrangement of several covered stents 300, the exact position inrelation to each other (ostia/orifice) is not as important as for knowncovered stents. Flexibility without risk for kinking is provided with orwithout extension covered stents 600.

Then, downstream the aorta there is proximally a covered stent 400 withtwo distal legs united into a single lumen body having a proximalorifice. The first leg of covered stent 400 is delivered running alongguiding element 10 for interconnection with the proximal orifice of thecovered stent 300, which in turn is previously distally interconnectedto the third leg 203 of the distally and upstream in the aorta arrangedand previously implanted covered stents 300. The other distal leg ofcovered stent 400 is delivered along guidewire 20. It is distallyinterconnected to the proximal orifice of the other covered stent 300,which in turn is previously distally interconnected to the second leg202 of the distally and upstream in the aorta. Thus the parallel coveredstents 300 are collected together in a single lumen.

A further covered stent 410, without side branches or legs is distallyinterconnected to the proximal orifice of covered stent 400. The furthercovered stent 410 is delivered over both the guiding element 10 andguidewire 20 which both are run inside this covered stent 410 throughone of the distal legs of covered stent 400 respectively. In case thecovered stents 300 include one or more guiding element(s) 10, previouslyused for the extension covered stents into the neck vessels, these oneor more guiding element(s) 10 will also be run through the lumen ofcovered stent 410.

Overlap of covered stents 400, 410, 420 can be adapted duringimplantation to accommodate the patient aortic anatomy.

Next in downstream aorta direction is a two-legged covered stent 420 isimplanted/provided and branching the blood flow into two proximal legsfrom a distal common lumen and orifice interconnectable to proximalorifice of the distal covered stent 410 previously implanted. Guidingelement 10 runs inside the first leg. Guidewire 20 runs inside the otherleg. The two legged stent is delivered over the two latter in a deliverycatheter, which may be the same as used for delivery of previouslydistally delivered modules.

And finally, at the bottom of the drawing, two covered stents 310, 320are illustrated, with two side branches 3 each. These two covered stents310, 320 are described in more detail below with reference to FIGS. 5 aand 5 b respectively

The first covered stent 310 is delivered by means of guide element 10(catheter slid over guide element 8 to the leg of covered stent 420). Afurther delivery catheter may be used for this purpose, such asdescribed with reference to FIG. 8 with the difference that the guideelement runs all the way through the first covered stent 310. One ormore further guide element(s) 10 may be attached to one or more of theside branches of the first covered stent 310 for delivery of extensioncovered stents 600 extending into side vessels, see FIG. 2 whenimplanted.

The second covered stent 320 is delivered by means of guidewire 20. Adelivery catheter is again used for this purpose, such as describedabove. A further guide element may be attached to one or more of theside branches of the second covered stent 320 for delivery of extensioncovered stents 600 extending into side vessels, see FIG. 2 whenimplanted.

The proximal end of the two covered stents 310, 320 are interconnectedto two distal legs of a two legged covered stent 430 to provide a liquidpath thereby. Guidewire 20 and guide elements 10 run accordingly throughcovered stent 430.

As described above, the system 100 is thus positioned as shown in FIG. 2.

In an example a method of interconnecting a plurality of covered stentsis provided which can be performed either in vivo and/or in vitro.

In an example, before assembly, and/or during assembly, the coveredstents of the system 100 are sorted and placed in the correct order forassembly. In an example, and if assembled during implantation, a numberof catheters 30 may be used as described and needed. The components ofthe system may be provided as a kit with suitable numbering tofacilitate implantation for the surgeon. The kit components andcomposition may be computer plant prior to the implantation procedure. Asoftware may be provided to support the surgeon and/or clinicalpersonnel to perform the procedure. The surgeon may virtually plan theprocedure in advance. Sequence of components, preferably with numbers inthe kit components, and procedural steps may then be suggested bysoftware during the implantation procedure. Quality assurance may beprovided by entering into the software feedback of components used andsteps performed. X-ray images and timestamps and other medical equipmentmeasurement or input data may be saved too. The procedure may thus beefficiently performed and documented at the same time.

Although not shown in FIG. 1 , further navigation elements 20 and/orguiding elements 10 may be provided for navigation of the side branches3 and aligning of the side branches 3 with branch vessels, as explained.To make it easier to see which navigation element 20 or guide element 10that goes to a certain covered stent, leg or side branch, eachnavigation element and guide element is labelled in an example.

Modular covered stents, as described with the system 100 will now bedescribed in more detail. As mentioned above, the modular stents maybearranged differently in other systems than the one illustrated in thefigures. Some modular covered stents may be provided individually forconnection to known units, or individually, depending on the targetsite, treatment need and/or patient history.

FIG. 3 illustrates a covered stent 200 with three legs 201, 202, 203,and a navigation element 20 and guiding element 10 in from of a suturefor easy navigation to all three legs. FIGS. 3 and 8 illustrate examplesof how one or more (one shown) guiding element 10, such as a suture, mayrun through a covered stent during implantation of a system 100 ofcovered stents.

The three legs 201, 202, 203 are provided for connection to three aorticarch side vessels: one into the neck artery, and two through channels(when assembled) with side branch vessel connection. The three legs 201,202, 203 may have different lumen diameter and length. Overlap withcovered stents 300, 600 may be chosen according to patient anatomyduring the implantation procedure.

The pre-attached guiding element 10 extending into one leg (203) andinto another leg (201) allows for a direct intubation of a side vessel.Direct access is provided to all side branches of the prosthesis withoutthe difficulty of locating the side branches with the open legs of suchan implant. This has hitherto been difficult to navigate, due to thelength of the delivery catheter where the operator usually has nofeeling for targeting to a side vessel. Also the pulsating blood flowduring the procedure, and other procedural difficulties of intubation ofside branches, are less relevant than for known covered stent. 3D to 2Dvisualization difficulties are avoided, less x-ray dosage is needed, theprocedure is provided with significant time reduction, and reducedpatient risk.

The guiding element 10 is used for guiding further covered stents to aconnection location so that the covered stents can be connected togetherinto to the system 100 of covered stents. More about FIG. 8 can be foundbelow.

In an example as illustrated in FIG. 3 , the navigation element 20, herea guide wire, runs inside and through the three legged covered stent 200via a leg 202. During implantation of the system 100, the navigationelement 20 is inserted far enough into the vessel so that any coveredstent can follow the navigation element 20 to a desired target sitelocation.

In an example, the covered stents are guided to their respectiveposition by sliding them along a navigation element 20 inside a deliverycatheter. Upon release out of the distal catheter end, the coveredstents are expanded into place and implanted at that target site.Restraining members 8 may be provided.

FIG. 3 further illustrates that one or more guide elements 10, such assutures, may be attached to the covered stent 200. In the figure, thesuture 10 is attached inside the second leg 4 and extends out throughthe third leg. The guiding elements 10 have, as discussed above, asimilar purpose to the purpose of the navigation element 20 of guidingdelivery catheters for delivery of covered stents such that they can beconnected to form the system of covered stents 100.

The operator can easily locate the two legs and navigate further coveredstents to any of the two legs. The operator can via the guiding element10 navigate a first further covered stent 600 to the leg 201 where theguiding element 10 is attached. When the first further covered stent 600is correctly positioned and connected to the three-legged covered stent200, the operator can, via the same guiding element 10, navigate asecond further covered stent to the leg 203 where the suture exitsproximally from the three legged covered stent 200. The navigationelement 20 ensures that the operator can locate also the third leg, asshown in FIG. 3 , and deliver units that way as desired.

Generally, one advantage of using the guiding element 10, such a suture,instead of or in addition to the navigation element 20, such as aguidewire, is that a suture or a wire is provided flexible and can bebent and manipulated as desired without breaking. The navigation element20 when being a guidewire is usually stiffer such that it can exert adistal force from the operator for e.g. pushing along a vessel from apuncture site. A catheter is then thread over the guide wire and movedalong the guide wire. The guide wire may then be removed from thecatheter for delivery of a unit through the catheter.

The flexible characteristics of the guiding element 10 allows for e.g.the covered stent to be placed into positions and/or navigated arounde.g. corners in the covered stent and/or in a vessel and/or side branch3. The guiding element 10 runs in embodiments outside of a deliverycatheter lumen through which a unit is deliverable. Alternatively, or inaddition, a guiding element may run through the same lumen as the lumenfor delivery of a unit.

Preferably the distal tip of the catheter 30 then has a design such thatthe distal orifice extends beyond the attachment point of the distal endof the guiding element 10. This can for instance be provided by alongitudinal recess (not shown) in the catheter lumen wall into whichthe guiding element 10 fits. The distal end of the catheter 30 with itsdelivery orifice may then protrude beyond the attachment point 11 wherethe proximal end of the recess will be positioned when the deliverycatheter 30 is pushed distally forward. The recess may be a longitudinalslit. The recess may have at least a V-shaped portion to allow theguiding element 10 to be caught or introduced more easily in the recess.The catheter 30 may be slightly wiggled and/or rotated to allow theguiding element 10 to enter the recess.

As explained previously in relation to guiding element 10, the position11 where the distal end of the guiding element 10 is permanently orreleasably attached to the covered stent is advantageously provided witha marker, so that it can easily be seen during scanning by e.g. MRI, CTor X-ray. The connection point 11 serves as a stop unit for guidingelement 10 to prevent a tangible resistance and further distaladvancement of catheter 30 by the surgeon during the delivery procedure.

FIG. 4 illustrates a covered stent 1 with a side branch and is anexample a covered stent 300 with a side branch 3 of the exemplary system100 (FIGS. 1 and 2 ).

The covered stent 1 has a main body 2, which is a covered stent, and alateral side branch 3 connected to the main body 2. The side branch 3protrudes out from the main body 2 and is flexible and expandable. Oneadvantage of the side branch 3 being flexible and expandable is that theside branch 3 is easily movable in at least one dimension independent ofthe movement of the main body 2 such that a branch vessel can be foundand more easily aligned with during implantation to enter into with theside branch 3.

FIGS. 14A-D are a perspective view, a top view, a lateral view and afront view of an example of a modular covered stent 300 with a singlelateral side branch. Alternatively, or in addition, the covered stent 1may have more than one side branches 3, like covered stents 310, 320shown in FIGS. 5 a and 5 b .Connection section 3 a providing a degree ofmovement of branch 3. This improves long term stability and maycontribute to prevent clot formation.

Alternatively, or in addition, the covered stent 1 has a plurality oflegs and wherein at least one of the legs comprises a side branch 3.Thus, in an example (not shown) the covered stent 1 has a plurality oflegs and each leg comprises a side branch 3. In an example the sidebranch 3 is deflated, collapsed or folded and may look like the sidebranch 3 of FIG. 3 . Collapsed may include radially and/orlongitudinally collapsed states, allowing reduced cross-section fordelivery.

In an example the shape of the side branch 3 when collapsed may be domeshaped, or substantially half sphere shaped, see FIG. 7 for anon-limiting example. This allows the covered stent 1 to be safer forinsertion during operation and/or navigation to a branch vessel thanknown devices of today since the side branch 3 does not have any sharpedges that can tear, rip or penetrate the branch vessel as known devicesof today. However, the branch vessel 3 is preferably only longitudinallyexpandable from a min body 2 and cylindrical in shape, as e.g. shown inFIGS. 1, 2, 4, 5 a, 5 b, 6, 8, 10, 11, 14, 15B,C, 20 .

The side branch 3 is configured so that its shape may be changed to fitthe branch vessel and allows for further extension away from the mainbody of the covered stent into the branch vessel with for exampleanother covered stent or covered stent. Such expanded state includes inparticular a longitudinally expanded shape of the branch 3, such asschematically illustrated in FIGS. 4, 5 a, 5 b, 9 and 10, 11, 14, 15,17,19, 20 . Transition from the longitudinally collapsed state to theexpanded state may be done by unfolding, stretching, spring effect orother similar operations of the branch 3, as illustrated in FIG. 6 .

FIGS. 5 a-b show two examples of a covered stent with more than one sidebranch in the expanded state. The covered stent 310 shown in FIG. 5 ahas two lateral side branches 3 protruding from the same side. Thecovered stent 320 in FIG. 5 b also has two side branches 3, but theyprotrude from opposite sides.

Other configurations of side branches are provided as needed foranatomical reasons at a target site. In an example, the side branches 3are distributed at any desired location on the main body 2. In anexample the locations are based on the layout of the vessel wherein thecovered stent 1 is going to be placed, and its side vessels. Althoughnot shown, the covered stent 1 may also have more than two side branches3. The side branches may have an angle inclined towards the side branch,i.e. an angle from the longitudinal axis of the main body other than 90degrees, e.g. between about 30 or 45 to below 90 degrees.

As will be explained more, further below, the lateral side branch 3 maybe expandable from a first protruding length or size to a secondprotruding length or size. This expansion may be independent of anexpansion of the main body 2, or vice versa, the expansion of the mainbody 2 may be independent of the expansion of the side branch 3. Thismeans that when the covered stent 1 with the side branch 3 is collapsedor folded, in one example the side branch 3 can be expanded or unfoldedwithout the main body 2 of the covered stent 1 being expanded orunfolded. In another example the main body 2 of the covered stent 1 canbe expanded or unfolded without the side branch 3 being expanded orunfolded.

As the side branch portion 3 of the covered stent 1 is in someembodiments flexible when extended, alignment with the side branchvessel can be less critical than with conventional covered stents.Thanks to the flexibility, navigation towards and/or into the sidebranch vessel is facilitated during implantation and when implanted bythe flexibility of the side branch 3, illustrated in e.g. FIGS. 7 and 11. Some misalignment of the orifice of the side branch 3 at the main bodyof the covered stent 1 in relation to the branch vessel orifice may becorrected by the path of the flexible laterally extending side branch 3.A blood communication path of the side branch 3 can be extended bymatingly engaging a further covered stent or covered stent graftinterconnecting at the distal end of side branch 3 and extending intothe side branch vessel.

FIG. 6 shows an illustration, bottom-top, of an example of a side branchwhich is self-expandable from a collapsed to an expanded shape. FIG. 6illustrates one example of a covered stent 1. The covered stentsdiscussed herein are in an example self-expanding, or in another exampleexpandable by another device, such as an inflatable balloon, a pusherunit, or the like. FIG. 6 illustrates three different side branches 3 atdifferent expansion lengths.

The covered stent 1 has a main body 2, which is a covered stent, and alateral side branch 3 connected to the main body 2. The side branch 3protrudes out from the main body 2 and is expandable and optionallyflexible and7or tiltable in an angle relative the main body longitudinalaxis and/or arranged in such angle when protruding from the main body 2.One advantage of the side branch 3 being flexible and expandable is thatthe side branch 3 is easily movable in at least one dimensionindependent of the movement of the main body 2 such that a branch vesselcan be found and more easily aligned with during implantation to enterinto the side branch 3.

In an example the covered stent 1 may have more than one side branch 3.In an example the covered stent 1 has a plurality of legs and wherein atleast one of the legs comprises the side branch 3. Thus, in an examplethe covered stent 1 has a plurality of legs and each leg comprises aside branch 3. In an example the side branch 3 is deflated, collapsed orfolded and may in an example look like the side branch 3 of FIG. 7 .Collapsed may include radially and/or longitudinally collapsed states.

In an example the shape of the side branch 3 when collapsed is domeshaped, or substantially half sphere shaped, such as shown in FIG. 7 .The above allows the covered stent 1 to be much safer for insertionduring operation and/or navigation to a branch vessel than known devicesof today since the side branch 3 does not have any sharp edges that cantear, rip or penetrate the branch vessel as known devices of today.

The side branch 3 is configured so that its shape may be changed to fitthe branch vessel and allows for further extension away from the mainbody of the covered stent into the branch vessel with for exampleanother covered stent or covered stent. Such expanded state includes inparticular a longitudinally expanded shape of the branch 3, such asschematically illustrated in FIGS. 4, 5 a, 5 b, 6, 8, 9 and 10, 11, 14,15, 17, 19, 20 . Transition from the longitudinally collapsed state tothe expanded state may be done by unfolding, stretching, spring effector other similar operations of the branch 3, as illustrated in FIG. 10 .

In an example expansion may be obtained by a spring effect of thecovered stent 1 and/or the side branch 3, as e.g. illustrated in FIG. 10. The expansion may come to an equilibrium position within the vessel inan example.

The lateral side branch 3 is preferably integrally formed with the mainbody. The side branch is in some embodiments provided with a springelastically self-expanding the side branch 3 in the longitudinaldirection of the side branch 3 without radial expansion. The spring maybe a helical spring wound as shown in the FIGS. 15B,C. A spring likestructure can be preferably provided to help a side branch expand fromthe prosthesis main body, such as perpendicular to it, or alternativelyat a different angle than 90 degrees from the longitudinal axis of themain body.

The covered stent 1 or side branch 3 may include wires that are suitablyarranged as a stent/supporting frame part of the covered stent. In anexample the wires may have a U shape in a longitudinal direction of thecovered stent. In another example the wires may be helically wound, asillustrated in FIG. 10 . In yet other examples they may be arranged insuitable patterns, like zigzag patterns etc.

In an example the wires may be wires interwoven with the covering. Thewires may form a mesh, like a knitted pattern or a braiding. The wiresmay also be laser cut to form the springy pattern of the stent part.

Alternatively, or in addition, the wires or other expansile componentsof the present device may be made of a shape memory material. The shapememory effect of such wires may provide for a change of shape, such ascollapsed to expanded shape, by means of known triggers liketemperature. Suitable materials include Nitinol, CrMo alloys, shapememory polymers, etc. Shapes of components of embodiments made of suchmaterials may be provided by heat treatment. Components of embodimentsof such materials may rely solely on elastic or superelastic properties(e.g. Nitinol) for a change of shape from a collapsed or compressedconfiguration to an expanded, released, configuration.

When the covered stent 1 is made in a resilient configuration, uponexiting a delivery catheter, it will resiliently expand out from themain body of the covered stent, as for instance described below withreference to FIG. 10 .

FIG. 7 illustrates how a covered stent with a folded or collapsed sidebranch can be used to find a branch vessel. The volcano shape of sidebranch 3, is as mentioned above only an example. A guide wire 20 is fedthrough the side branch and a catheter is thread over the guidewire.Then a delivery passage through the side branch is provided.

Guidewire 20 may be brought into place via a catheter 30 earlier guidedby the guiding element 10 to the target site, e.g. at the side branch 3.Catheter 30 may be retracted and a different catheter be threaded overthe guidewire thus put in place by means of guided catheter 30.

FIG. 8 illustrates a covered stent 300 with a side branch 3, and acatheter with a guiding mate 9 for guiding the catheter 30 for easynavigation of the side branch.

In an example, illustrated in FIG. 8 the catheter 30 comprises a guidingmate 9 which is configured to run over the guiding element 10 and/ornavigation element 20 when guided by the guiding/navigation element tothe side branch 3.

In this example the guiding mate 9 is a length of tube attached to thecatheter 30. Alternatively, the guiding mate 9 is integrally formed withthe catheter, e.g. by suitable extrusion of the tubular member of thecatheter. The guiding mate may be formed as an inner lumen, and/orintegrated with the catheter wall. The guiding mate 9 may be integralwith the catheter, or alternatively a separate element suitably attachedto the guiding element 10, e.g. by adhesion, welding, or othermechanical attachment means. The catheter 30 may be a multi lumencatheter with at least one lumen. Preferably, it is a double lumencatheter. An example is schematically illustrated in FIG. 16 . A firstlumen 30a is provided for delivery of a unit, deployable through thedistal orifice of the first lumen. A second lumen, as guiding mate 9, isprovided for threading over the proximal end of the guiding element 10towards the distal end and attachment point thereof as described above.The second lumen has preferably an orifice provided proximally of thedistal orifice of the first catheter lumen. In this manner, the distalorifice of the first lumen is positionable distally beyond theattachment point of the guiding element 10.

Alternatively, or in addition, the guiding mate 9 comprises a ring,eyelet, snarl, or loop for threading through of the guiding element 10.An inner diameter of the guiding mate 9 is matched to receive an outerdiameter of the guiding element 10 with some tolerance to avoid too muchfriction between the two elements for sliding motion along each other.

The guiding mate 9 is a unit for matingly receiving the guiding element10 there through for being slidingly movable along the guiding mate 9 toand from the guiding mate’s distal end where it is preferably attachedto a covered stent. The guiding element 10 is configured to be threadedthrough the guiding mate 9 for being slidingly moveable along theguiding mate 9. Threading through of the guiding element 10 is suitablydone outside of the patient at the proximal end of the guiding mate,e.g. a suture, thread, filament or wire, of e.g. multifilament strands,that are for instance braided together, to form a flexible guiding unit10.

Alternatively, or in addition, the guiding mate 9 can be a lumen of adual (or multi) lumen catheter or any other suitable element which isconfigured to allow sliding on the guiding element 10 and preferablydoes not damage the vessel or lumen it is used in.

The guiding mate 9 has advantageously a distal end or opening which isarranged a suitable length remote, i.e. proximal, of the distal end ofthe catheter 30. In this manner, the distal end or opening of thecatheter 30 may advance further distally than the guiding mate 9 when atthe end position of the guiding element 10 and/or navigation element 20,e.g. at a fixation point, such as a knot of a suture, where the guidingelement 10 and/or navigation element 20 is distally affixed to a coveredstent, e.g. at an orifice or opening thereof as described andillustrated herein.

The guiding mate 9 has thus a distal end or opening which preferably isarranged at the catheter proximal (at a distance) of a distal end ordistal opening of the catheter 30.

In this manner, it is ensured that the distal end of catheter 30 may bepositioned distally of the connecting point 11 for instance enters aside branch into which a delivery is to be made through the lumen of thecatheter, e.g. a covered stent into a side vessel and assembly as wellas interconnection with a main vessel covered stent in which thefixation point is located. In this manner, the side vessel covered stentcan be delivered to the right location, i.e. branch opening, of the mainvessel covered stent with minimal X-ray dosage as no 3D visualization isneeded for the operator.

In an example, also related to FIG. 8 , a guiding element 10 is attachedto the side branch 3. This allows any further elements to be implanted,preferably covered stents, to be easily delivered through a catheter 30with guiding mate 9 for e.g. being connected to the side branch 3 ordelivered out of a side branch 3 with minimal effort and improvedreliability as well as patient safety.

As shown in FIG. 8 , the guiding mate 9 is in some embodiments placed ata distance from the distal end of the catheter 30. One advantage withthe guiding mate 9 at a distance from the distal end of the catheter 30is that the catheter 30 may then reach further than the position 11 ofthe attachment of the guiding element 10. E.g. if the guiding element 10is attached at the side branch 3, the catheter can reach further outthrough the side branch 3. This enables easy access for positioning andconnecting e.g. an extension covered stent 600 at the side branch 3.

The distal end portion of the catheter 30, preferably distally of theguiding mate 9 distal end, can additionally, or alternatively, be bent,see FIG. 8 . This allows for a desired exit angle of the orifice of thedelivery catheter 30 at its distal end, for instance substantiallyperpendicular in relation to a longitudinal axis of a main body 300.

However, the guiding mate 9 distal portion or end may in someembodiments reach all the way up to the distal end of catheter 30.Improved, advantageous minimally invasive delivery of elements through aside branch is ensured in any case.

In an example, as illustrated in e.g. FIGS. 9 a,b,c, 10 and 11, 15 and17 the covered stent 1 is provided with a restraining member 8 thatprevents the covered stent 1 from expanding until release of therestraining member provides for controllably expanding the covered stent1.

In an example the restraining member 8 is made of a PTFE or Gore-Tex®material. The restraining member 8 ay be provided as a flat sheet,fabric or nonwoven material releasably arranged around a covered stentfor delivery. Alternatively, any other suitable biocompatible materialsmay be chosen for the restraining member that can be inserted into thebody and easily manipulated as well as protect any vessel or lumen fromthe covered stent 1 during deployment.

FIGS. 9 a-c illustrate an example of a restraining member. For instancea covered stent 200 that is self-expandable may be provided with suchrestraining member 8. The covered stent transitions controllably from acollapsed to an expanded shape by removal of the restraining member.

In an example, the removal of the restraining member 8 is done by simplypulling on a string which then releases a seam holding together a sheetof the restraining member 9 arranged around the covered stent. Pullingthe release string unfolds the restraining member along the seam,depending on the distance pulled on the string. The restraining memberunfolds thus partially or fully, as for instance illustrated in FIGS. 9a-c . In an example more than one string / seam is used to select wherethe restraining member 8 is removed from restraining the covered stentand/or side branch 3.

Alternatively, or in addition, the restraining member 8 is configured tobe partially removable so that the expansion of the covered stent 1and/or side branch 3 can be selected individually. This is illustratedin FIG. 9 a , where the covered stent is fully restrained by therestraining member 8. In FIG. 9 b the restraining member 8 is shown aspartly opened and thereby allowing the covered stent to partiallyexpand. Partially expanded stent may still be repositioned if sodesired.

The example illustrated in FIG. 9 c shows more than one restrainingmember 8 for restraining portions of a covered stent. Each restrainingmember is thus provided for restraining different parts of a coveredstent, here in the example the three-legged covered stent 200. In thisway, the three legs can easily be expanded individually, one at a timeor simultaneously. In the same manner a covered stent 1 with a sidebranch 3 can be partially or fully expanded by releasing it from e.g. arestraining member around the main body 2 and another restraining member8 around the side branch 3. An example is described below with referenceto FIG. 18 .

The collapsed unit (FIG. 9 a ) is introduced to a target site through adelivery catheter that may have a guiding mate 9 slidable along aguiding element 10 as described above. The assembly shown in FIG. 9 (andsimilar others) may include one or more guiding mate(s) 10 itself, ase.g. shown in FIG. 3 . The latter guiding element(s) 10 are led outsidefrom inside the restraining member 8 from the covered stent (here 200),and further proximally towards the proximal end of the catheter, outsidethe patient. Thus further elements may advantageously be deliveredthrough the covered stent when implanted, as described herein.

In an example more than one string is used to select where therestraining member 8 is removed from the covered stent 1 and/or sidebranch 3.

Alternatively, or in addition, the string of the seam of the restrainingmember is one of guiding element(s) 10 when attached to the coveredstent 200. The guiding element then 10 is attached distally to thecovered stent, as e.g. in FIG. 3 , runs proximally out of an orifice ofthe covered stent 200. Then it is folded back, runs inside theprotection unit 8. Turning back proximally again, it provides thereleasable seam. When pulled and removed from the seam, i.e. therestraining member is released, it is further pulled back, leaving aguiding element 10 for use as a catheter guide. This synergetic guidingelement 10 and seam of a protective unit / restraining member 8 isadvantageous in that the number of components is reduced that needs tobe drawn outside of the patient, amongst other advantages. Therestraining member 8 is configured to be partially removable so that theexpansion of the covered stent 1 and/or side branch 3 can be selectedindividually. This is illustrated in FIG. 9 a , where the covered stent200 is fully restrained by the restraining member 8. In FIG. 9 b therestraining member 8 is partly opened and thereby allowing the coveredstent 200 to have partially expanded, here along its length.

Another example is illustrated in FIG. 9 c , where more than onerestraining member 8 is used to restrain different parts of thethree-legged covered stent. In this manner, for instance one or more ofthe three legs of covered stent 200 can easily be expanded individually,one at a time or simultaneously. In the same manner a covered stent 1with a side branch 3 can be partially or fully expanded by releasing itfrom e.g. a restraining member around the main body 2 and anotherrestraining member 8 around the side branch 3 (not shown)

FIG. 10 illustrates how a sheath may be used to hold the covered stentin a collapsed or folded manner, and to controllably release the coveredstent, partially or fully.

FIG. 10 illustrates how the covered stent 1 is first released fromrestraining member 8 from one side, the right hand side as shown in thetop part (a) of FIG. 10 . As illustrated in the middle and bottom parts(b and c) of FIG. 10 , the part of the covered stent 1 that comprisesthe side branch 3 is then released. This is further illustrated in FIG.11 , where the covered stent 300 is partly released from the restrainingmember 8 to allow easy fitting of the side branch 3 with a branchvessel. When the part of the covered stent 300 that comprises the sidebranch 3 is released from the restraining member 8, the side branch 3 isaligned with the branch vessel and is then expanded into the branchvessel. The covered stent 300 is then fully released from therestraining member 8, as illustrated in the bottom part of FIG. 11 . Acovered stent 600 extending further into the side vessel is showndelivered and deployed as described herein.

FIG. 11 illustrates an example of a covered stent 1 which can be used inan easy method of finding a branch vessel. The covered stent 300 ispushed fully out of a delivery device 30, such as a catheter, and themain body 2 of the covered stent 1 is expanded.

The side branch 3 is in examples expanded by pushing it outwards and/orconfigured to expand by itself, as disclosed above and illustrated ine.g. FIGS. 6, 7 and 9 .

A further pushing element (not shown) can used to push the flexible sidebranch 3 in a desired direction and outwards, so that it expands from afolded or collapsed state. This applied in case the side branch 3 is notself-expandable.

In case of a self-expandable side branch 3, it will expand radiallyoutwards from the main body as soon as it is released from the deliverycatheter (30), and/or a restraining unit 8 is removed.

For easier alignment with a branch vessel, the covered stent side branch3 can be provided with a marker 21, as e.g. illustrated in FIG. 3 . Themarker 21 will make it visible to the operator when the side branch 3 islevel or aligned with a branch vessel. By having only one marker at theside branch 3 it will be easier for the operator to align the coveredstent 1 to its desired location by use of an imaging device, such asX-ray, than today’s covered stents having a plurality of markers thatneed to be brought in alignment in fluoroscopy. The marker 21 is inexamples any fiducial marker visible under common type if imagingdevices used in healthcare or covered stent placement such as MRI,X-ray, Ultrasound, and so on. Covered stent structures usually arethemselves difficult to see under e.g. fluoroscopy. Markers may e.g.made of gold or similar materials allowing good visibility in suchimaging.

In an example, the side branch 3 is folded or collapsed and restrainedby a guide element 10, such as a suture 10. The guiding element 10 isfor instance wrapped around the side branch 3, and is releasableconnected on the inside of the side branch 3 or otherwise attached tothe side branch 3 causing it to be releasably folded or collapsed.Pulling the guiding element proximally then releases the side branch 3from the collapsed state to the expanded state. Guiding element 10remains in place for use as a catheter guide.

In an example the covered stent 1 is aligned with a branch vessel bymoving the main body 2 of the covered stent 1, as e.g. illustrated inFIGS. 9-11 . In an example, this is achieved by the covered stent 1 onlybeing partially pushed out of the catheter 30 and/or partially freedfrom the restraining device 8 as also disclosed above, so that thecovered stent 1 can be moved by moving the catheter 30, or otherwisemoved by e.g. a pusher wire, e.g. illustrated in FIGS. 9 and 10 .Preferably, the side branch 3 is self-expandable.

In an example, the covered stent 1 is moved upwards until the marker 21on the side branch 3 aligns with the branch vessel. Then the coveredstent 1 is rotated until the side branch 3 enters the branch vessel.When the side branch 3 has entered the branch vessel the guiding element/ e.g. suture 10 is released, allowing the side branch 3 to expand intothe branch vessel, either by itself or by pushing it outwards.

In a further alternative example, the covered stent 1 is aligned with abranch vessel by navigating both the main body 2 of the covered stent 1and by navigating the side branch 3 of the covered stent 1.

FIG. 15A is a perspective and sectional view of a modular covered stent300 with a lateral side branch in a delivery configuration. FIGS. 15Band 15C are schematic views of deployment of the lateral side branch ofthe modular covered stent 300 of FIG. 15A before release of the mainbody. There are two layers of outer restraining members / sheath thatcover the prosthesis/ covered stent. A side branch outer restrainingmember 8 a to restrict the side branch prosthesis only. It wraps outsideof a first outer restraining member 8. It is only about a portion, suchas ⅓ of the length of the entire prosthesis. The first outer restrainingmember 8 covers the entire body of the prosthesis with a shape cut outon it to allow the side branch prosthesis to pop out. The side branchouter restraining member 8 a will be opened first to release side branchguidewire and side branch prosthesis. Once the side branch vessel islocated, the first outer restraining member 8 a can be opened to fullyexpose the prosthesis main body, as is illustrated in FIGS. 15B and 15C.The prosthesis delivery system is inserted and lined up with the sidebranch tip close to or directed towards the side branch vessel. Theposition of the prosthesis is adjusted if needed, e.g. by the help offiducial markers, optionally a guidewire can be used to find the sidebranch entrance. The side branch outer sheath 8 a is opened. The sidebranch outer sheath 8 a can be opened fully to release the side branchprosthesis. The side branch prosthesis fully expands. Then theprosthesis main body outer sheath 8 is opened to release the entireprosthesis. A two lumen catheter 30 can be brought over the guidingelement 10 to bring another guidewire into the side branch for theconnecting prosthesis delivery system. One of the lumens 9 will go overthe side branch guide element 10 to gain access to the side branchvessel. Once the two lumen catheter 30 is in place, another guidewirewill be introduced to the side branch through lumen 30a which can befreely move upwards for deeper access as described in more detail withreference to methods and procedures below.

FIG. 17A is a perspective and sectional view of a modular covered stent300 with a lateral side branch in another delivery configuration. FIG.17B is a schematic view of a release of a main body and lateral sidebranch of the modular covered stent 300. FIG. 18 is a schematic view ofa catheter tool for releasing a navigation unit from an extension of alateral side branch.

There is a single layer of outer sheath 8 covers the entireprosthesis/covered stent. The prosthesis exposure can be divided intothree stages:

-   First stage: The distal section of the outer sheath 8 is opened,    releasing about ⅓ of the prosthesis main body. The outer sheath 8 is    opened slowly to release the first section of prosthesis main body.    Adjust the position of the prosthesis can be done.-   Second stage: The outer sheath 8 is opened continuedly till the side    branch prosthesis 3 is fully exposed. Once the correct position is    found, the mid section of the outer sheath 8 is opened to release    the side branch 3. The side branch 3 is expanded. The outer sheath 8    is further opened till the side branch 3 prosthesis is fully exposed    and adjust its position if required. To open the tip of the side    branch prosthesis, loops provided are released from a bar that is    holding it. Once the loops are released from the locking mechanism,    the covered stent will expand resiliently and/or by shape memory    effect. The outer sheath 8 is continuedly opened till the main body    2 is exposed. Now, surgeon can deliver an expansion covered stent    600 to the side branch vessel. Expanding a section of the prosthesis    main body 2 before launching the side branch potentially may help    the surgeon on placing the guide wire in the side branch vessel.-   The last stage: Till the side branch prosthesis is in the side    vessel, the sheath 8 is fully opened.

FIG. 18 is a schematic view of a catheter tool for releasing anavigation unit from an extension of a lateral side branch. The distalend of the catheter 30 lumen may include a distal unit for releasableattachment of a branch 3. Branch 3 may for instance include attachmentmeans like loops 35. The attachment means like one or more wire orthread loops 35 are attached with the prosthesis side branch 3 distalend and can be releasably fixed to a locking part 38. The locking part38 can for instance be moved up or down relative a stop unit like theflange at the distal end shown in FIG. 18 . The locking part may includeone or more rods or struts longitudinally movable and engageable withthe loops 35. The locking part 38, like including the rods or struts,can be releasably locked with the attachment means like the loops 35,e.g. when moved up to the stop flange, such as shown. Release of thelocking unit to the attachment means may be provided by reversing themovement of the rod(s) in the opposite direction so the branch 3 isreleased and the catheter can be withdrawn proximally. A Central space39 is provided for passing a guidewire or covered stent there through.In this manner, the branch 39 can be moved by moving the catheter endwith the locking unit when attached to the branch. Movement ispreferably towards the branch vessel, away from the main body but mayalso be provided to withdraw the branch 3 towards the main body ifdesired to adjust to the anatomical situation. The catheter may beguided with guiding element 10 as described above.

An example of a side branch prosthesis 300 implementation can be asfollows:

-   Length of prosthesis side branch 3 may be approx. 15 mm-   Some other exemplary but not limiting measures are given in FIG. 14-   The pre-load guide element 10 feature:    -   ◯ It is secured with the side branch, preferably in a position        that assists to manipulate the orientation of the catheter to        matingly engage the guide element 10. The connection point is        e.g. at the distally oriented inner side of the branch 3 such        that the guide catheter 30 can be advantageously navigated        through the lumen of the branch 3 towards a side vessel orifice        or lumen.    -   ◯ The pre-load guide element 10 works as a guilder for a        catheter 30, e.g. the double lumen catheter shown in FIG. 16 to        reach the side vessel.    -   ◯ The pre-load guide element 10 is preferably configured to        unlock from the prosthesis easily.

An example of a visceral side branch 310 can be as follows:

-   The prosthesis side branch 3 can be provided to maintain a certain    angel in relation to the main body 2 longitudinal axis, e.g.    approximately a 30-dgree angle or a 45-degree angle to assist a    surgeon to enter a side vessel with the catheter 30.-   The inner diameter of a side branch may be in the range of about 7    mm,-   The side branch prosthesis 3 is provided to allow a certain level of    movement to allow adjustment to various connection angles towards    side vessels.

FIG. 12 shows flow charts of two examples of a medical procedure.

The method 700 comprises the steps of accessing 710a target site being avessel in a patient; delivering 720 a first covered stent to the insideof the vessel at the target site through a delivery catheter, whereinthe target site has a side branch vessel; delivering 730 a secondcovered stent to the first covered stent; connecting 740 the firstcovered stent to the second covered stent for providing a blood flow tothe side branch vessel. The delivery of the second covered stentincludes sliding a catheter 30 along a guiding element 10 to a positioninside a lumen of a side branch of the first covered stent; andexpanding the second covered stent for connecting to the first coveredstent. The catheter 30 with guiding mate 9 can be used for thedelivering of a guide wire. Once the guidewire is in place in the sidebranch and extends sufficiently long into the side vessel at the sidebranch, the catheter 30 may be retracted. A covered extension stent 600can then be delivered over that guidewire to the side vessel.

Alternatively, or in addition, the method 800 is provided. The secondcovered stent may have a side branch 3. The method includes delivering asecond covered stent to a side vessel through a side branch 3 of thefirst covered stent. The method 800 comprises the steps of accessing 810a target site being a vessel in a patient; delivering 820 a firstcovered stent to the inside of the vessel at the target site through adelivery catheter, wherein the target site has a side branch vessel;expanding 830 the side branch 3, delivering 840 a second covered stentto the first covered stent and through the side branch 3 to the sidevessel; connecting 850 the first covered stent to the second coveredstent for providing a blood flow to the side branch vessel. A catheter30 with a guiding element 10 can be used between steps 830-840 asdescribed above.

In a specific example the method includes delivering and assembling thesystem 100 as explained above and with a final layout illustrated inFIGS. 1 and 2 .

The method starts in the example with soft guidewire being inserted intoa vessel of a patient. Using a soft guidewire ensures that no part ofthe vessel is damaged during insertion. Further, the soft guidewire canbe bent and thereby be navigated through the vessel system of thepatient to a target site, here in the example the ascending aorta. Asexplained above other target sites in the body could also be chosen asan alternative.

Then, a first catheter is inserted, over the soft guidewire, into thevessel of the patient and navigated until it reaches the target site.Guided by the first catheter, a stiffer navigation element 20 is theninserted into the catheter and thus vessel of the patient.

The target site in the example is the ascending aorta where the threelegged covered stent 200 is then positioned via the delivery catheter inthe aortic arch. The delivered state, assembled with further componentsin the aortic arch is illustrated in FIG. 2 .

Then a three-legged covered stent 200 is collapsed or folded to fitinside the first catheter 30 and pushed along it with the navigationelement / guide wire 20 may running inside the main part of the coveredstent and extending out through one of the legs 201.

The three-legged covered stent 200 is provided with a guiding element 10attached inside one of the other legs, as described above. In an examplea location near or to the left of the aortic arch is preferred.

Each guide element 10 and navigation element 20 can be labelled at theend proximal end for easy identification. The proximally labelled end isconfigured to be outside of the patient during implantation.

Following, when at the correct position of the target site, the coveredstent 200 is pushed out of the catheter 30 and allowed to fully orpartially expand or unfold, as discussed above. It is rotated until thelegs match the main vessel and the neck branch vessels of the aorta. Andas explained above this alignment can be performed in various ways.

Next, when the three legged covered stent 200 is in place, the system100 can easily be built up with further modules. As discussed above thiscan be done in several ways and in this example two covered stents 1having side branches 3 and covered stents 600 for extending into thebranch vessel are deployed following the three-legged covered stent 200as described above with reference to FIGS. 1 and 2 .

In the example illustrated in FIGS. 1 and 2 an extension covered stent600 is navigated via the guide element 10 attached inside one of thelegs of the three-legged covered stent 200 and navigated through thethree-legged covered stent 200 and positioned so that it can extend outthrough the leg. Here the covered stent 200 is expanded and connected tothe leg in an overlapping manner.

Following, the first covered stent 300 with the side branch 3 is slidinto place along the guide element 10 and connected to the third leg203. After or before the deployment along the guide element 10 thesecond covered stent 300 is slid along the guidewire 20 and connected tothe second leg 202.

No aortic clamping stopping blood flow in the aorta or cardioplegia isnecessary. Blood flow through the aorta and the side vessels is notinterrupted during the procedure thanks to the parallel arrangement ofthe covered stents 300.

When delivering a covered stent the side branch(es) 3 are at the sametime navigated into place with the covered stent and expanded into, orat least towards the branch vessel. Following, any additional extensioncovered stent can be inserted based on the desired need to furtherextend into the branch vessel.

Next, a covered stent 400 with two legs is moved in a collapsed stateinside the first catheter 30 along guide wire 20 and guide element 10.The covered stent 400 is oriented so that the legs are positionedtowards the covered stents 300 already connected. Each leg is guidedalong one of the guide element 10 and the guide wire 20, so that eachleg can be guided to one of the previous covered stents 300 with sidebranches 3. When in place, the covered stent 1 is released from thecatheter 30 and allowed to expand.

Alternatively, the collecting covered stent 400 may be connected to theproximal end of the branched covered stent 300 prior to connecting theside branch and/or delivering an extension covered stent 600.

Next a tubular shaped covered stent 410, without legs or side branches,is pushed into place through the catheter 30, and navigated andconnected to the previous covered stent 400 in a similar manner but nowhaving both the guiding element 10 and the guide wire 20 running inside.Length of the assembled prosthesis is adjustable by a variable overlapof the covered stents chosen by the surgeon during implantation when theinterconnection of these is made.

Then a two-legged covered stent 420 is connected to the tubular shapedcovered stent 1 in the same manner. This two-legged covered stent 420 isoriented with the legs away from the covered stents already distallyconnected upstream the aorta. These legs run along the guiding element10 and the guide wire 20, respectively. The length of the assembledprosthesis is adjustable by a variable overlap of the covered stentschosen by the surgeon during implantation when the interconnection ofthese is made.

After connection of the two-legged covered stent 420, a covered stent310 with two side branches 3 is guided along the guiding element 10through a delivery catheter, in a manner similar to previously deliveredcovered stents 300. When the main body of the covered stent is inapproximately the right place, further navigation of the side branch 3is done to be rotationally correctly oriented towards the side vessels.The side branches 3 are thus aligned with the branch vessels andexpanded into the branch vessels. Distally, the covered stent 310 isconnected with one of the legs of the two-legged covered stent 420.

Then, a covered stent 320 with two side branches 3, and further guiding10 or navigation elements 20, is guided via the catheter 30, alignedwith branch vessels and connected to the second leg of the two-leggedcovered stent 420.

Finally, a last two-legged covered stent 430 is positioned and the twolegs are connected to the two covered stents 310, 320 with two sidebranches 3, in a similar manner as described above, by use of a deliverycatheter 30 and running along the guiding element 10 and the guide wire20, respectively.

When the system 100 is connected and complete, all remaining navigationelements 20 and catheters 30 are removed from the patient. Guideelements 10 may be distally cut and remaining length left in place,preferably for subsequent biodegradation.

In an example, illustrated in FIG. 2 , a complete system 100 is shownassembled and implanted inside an aortic arch of a patient. As can beseen, the different covered stents 1 have been connected to each otherand side branches 3 have been extended into branch vessels and furtherextended with covered stents 1.

Further proximal covered stent modules (not shown), e.g. for iliacartery reconstruction or repair, may be provided and implanted, such asconnected to the proximal end of the covered stent 430.

FIG. 13 illustrates a method for navigating a covered stent 1 to abranch vessel. The method 900 comprises the steps of providing 910 thecovered stent 1, as discussed above, and navigating 920 the lateral sidebranch 3 into a branch vessel by moving the lateral side branch 3.

In an example this is performed by using an elongated navigation element20, as also discussed above. In one example it is performed using aguide element 10 and a catheter 30 with a guiding mate 9, as describedin relation to FIG. 8 .

The method may further comprise the step of expanding the lateral sidebranch 3 from a collapsed state into the branch vessel when navigated tothe desired position at the branch vessel. As described in relation toe.g. FIGS. 9-11 , this may be done by navigating the covered stent 1 sothat the side branch 3 is aligned with a branch vessel, then expandingthe side branch 3 into the branch vessel, and finally expanding the restof the covered stent 1.

In an example the method further comprises the step of interconnectingan expansion element at the lateral side branch 3 and into the branchvessel for further extension into the branch vessel. The expansionelement may be a covered stent 1.

Further examples of methods and procedures are given below:

A method is provided for navigating a covered stent to a branch vessel.The method includes providing a covered stent 200, 300, 310, 320 andnavigating the lateral side branch into or towards a branch vessel bymoving the lateral side branch using a guide element 10. The method mayinclude expanding a covered stent delivered through the lateral sidebranch 3 from a collapsed state into the branch vessel when navigated inposition at the branch vessel. The method may include interconnecting anexpansion element 600 at the lateral side branch and into the branchvessel for further extension into the branch vessel, wherein theexpansion element preferably is a covered stent.

A method is provided for interconnecting a plurality of covered stents.The method includes providing a covered stent having a bendable guidingelement connected at an exit of a side branch. The method may includeinterconnecting a plurality of such covered stents including sliding acatheter by means of a guiding mate 9 along the guiding element to theexit of the side branch and delivering another covered stent through thecatheter along the bendable guiding element for interconnection ofcovered stents. The covered stents preferably have a same dimension atthe interconnection.

A medical procedure is provided including accessing 710 a target sitebeing a vessel in a patient; delivering 720 a first covered stent to theinside of the vessel at the target site through a delivery catheter,wherein the target site has a side branch vessel; delivering 730 asecond covered stent to the first covered stent; connecting 740 thefirst covered stent to the second covered stent for providing a bloodflow to the side branch vessel, wherein the delivery of the secondcovered stent includes sliding a catheter along a guiding element 10 toa position inside a lumen of a side branch of the first covered stent;and expanding the second covered stent for connecting to the firstcovered stent.

A medical procedure is provided including accessing 810 a target sitebeing a vessel in a patient; delivering 820 a first covered stent to theinside of the vessel at the target site through a delivery catheter,wherein the target site has a side branch vessel; expanding 830 the sidebranch 3; delivering 840 a second covered stent to the first coveredstent and through the side branch 3 to the side vessel; and connecting850 the first covered stent to the second covered stent for providing ablood flow to the side branch vessel.

Another example of a delivery procedure is as follows:

-   1. Inserting a delivery system via an introducer sheath into a    patient’s body.-   2. Opening an outer sheath 9 and removing from a proximal end of a    prosthesis towards a side branch prosthesis direction. Keep opening    till the side branch prosthesis is released and expanded fully.-   3. Stopping opening till the side branch prosthesis is fully    exposed.-   4. Adjusting the position of the prosthesis for initial matching.-   5. Inserting a double lumen catheter 30 over a pre-loaded guide    element 10 and allow it travel to the side branch prosthesis, till    it hits the end at connection point 11.-   6. Insert an additional guidewire via the double lumen catheter 30    and make it protrude from the side branch 3.-   7. Optionally performing further adjustment of the position of the    prosthesis.-   8. Once the position of the side vessel is identified and confirmed,    advance the additional guidewire forward to secure the position.-   9. Once the additional guidewire is securely staying in the side    vessel, remove the double lumen catheter and deliver the connecting    prosthesis 600 by using the additional guidewire.-   10. Once the connecting prosthesis 600 is in side vessel and fully    expanded, remove the rest of the outer sheath 9 of the previous    prosthesis releasing it entirely.-   11. Unlock the guiding element 10 from the side branch prosthesis    and remove all guidewires and delivery system from the patient’s    body.

The present disclosure has been described above with reference tospecific examples. However, other examples than the above described areequally possible within the scope of the disclosure. Different methodsteps than those described above, performing the method by hardware orsoftware, may be provided within the scope of the disclosure. Thedifferent features and steps of the disclosure may be combined in othercombinations than those described. The scope of the disclosure is onlylimited by the appended patent claims.

What is claimed is:
 1. A covered stent comprising a lateral side branchextending from a main body of the stent, a supporting frame in thelateral side branch, the supporting frame having a frame pattern with anasymmetrical design for improved collapsibility of the stent.
 2. Thecovered stent of claim 1, wherein the frame is made of nitinol.
 3. Thecovered stent of claim 1, wherein the frame is a laser cut structure. 4.The covered stent of claim 1, wherein the pattern has a region without asupporting frame.
 5. The covered stent of claim 1, wherein the sidebranch comprises a connection section configured to provide a degree ofmovement of the side branch.
 6. The covered stent of claim 1, whereinthe side branch comprises a connection point configured to connect aconnecting element.
 7. A covered stent comprising a lateral side branchextending from a main body of the stent, a supporting frame in thelateral side branch, the supporting frame having a frame pattern of twohalves such that the branch is collapsible in a middle region.
 8. Thecovered stent of claim 7, wherein the frame is made of nitinol.
 9. Thecovered stent of claim 7, wherein the frame is a laser cut structure.10. The covered stent of claim 7, wherein the pattern has a regionwithout a supporting frame.
 11. The covered stent of claim 7, whereinthe side branch comprises a connection section configured to provide adegree of movement of the side branch.
 12. The covered stent of claim 7,wherein the side branch comprises a connection point configured toconnect a connecting element.
 13. A covered stent comprising a lateralside branch extending from a main body of the stent, a supporting framein the lateral side branch, the stent having a region without asupporting frame.
 14. The covered stent of claim 13, wherein the frameis made of nitinol.
 15. The covered stent of claim 13, wherein the frameis a laser cut structure.
 16. The covered stent of claim 13, wherein thepattern has a region without a supporting frame.
 17. The covered stentof claim 13, wherein the side branch comprises a connection sectionconfigured to provide a degree of movement of the side branch.
 18. Thecovered stent of claim 13, wherein the side branch comprises aconnection point configured to connect a connecting element.